KanjiJLPT N1
Forge

forge, discipline, train

Mnemonic

Only the highest grade of gold is worthy to forge into a legendary blade. Lower grade gold crumbles under the hammer, but the finest gold sings as you forge it—each strike perfecting its shape, each blow tempering its strength.
Additional thoughts
Picture a blacksmith sorting bars of gold by grade, tossing aside impure ones. Only top-grade gold earns the honor of being forged. The repeated hammering mirrors rigorous self-discipline.
Quick recall
Top grade gold is chosen to forge into a legendary blade.

Details

The keyword for 鍛 is forge. This kanji refers to the process of heating and hammering metal to shape, strengthen, and refine it, as a blacksmith does when creating tools or weapons. By extension, it also carries the meaning of disciplining or training oneself rigorously, much like tempering steel through repeated effort. The idea of forging thus encompasses both the physical craft of metalworking and the metaphorical sense of building strength and skill through persistent hard work.
On'yomi
たん
Kun'yomi
きた.える